Overlay network technologies, such as Virtual Extensible Local Area Networks (VXLANs), offer a highly scalable solution to managing cloud computing deployments by allowing OSI layer 2 networks to expand beyond layer 3 network boundaries through network virtualization. Layer 2 data traffic, such as Media Access Control (MAC) Ethernet frames, can be encapsulated within layer 3 packets, such as User Datagram Protocol (UDP) packets, to travel across layer 3 boundaries to reach its destination within the overlay network.
Various tunnel endpoints within the overlay network, such as Virtual Tunnel Endpoints (VTEPs), can terminate overlay network packets by encapsulating and de-encapsulating packets through MAC-to-UDP encapsulation. Each tunnel endpoint may be provided with a unique IP/MAC address pair to make the encapsulation and routing encapsulated packets within the overlay network possible. In addition, all the tunnel endpoint IP addresses in the overlay network may need to be stored in lookup tables at every one of those tunnel endpoints so that those tunnel endpoints can determine where to transmit encapsulated traffic. However, as the number of tunnel endpoints in a given overlay network increases, these tables also need to scale linearly, which can consume a large amount of resources at the tunnel endpoints.
Maintaining a large number of lookup or routing tables can be a challenge when new endpoints, such as servers and virtual machines (VMs), are added to the overlay network, existing endpoints are removed from the network, or some of the endpoints migrate from one tunnel endpoint to another within the network. Whenever such changes occur in the network topology, many if not all lookup tables residing in tunnel endpoints throughout the overlay network may require an update, a modification, or a synchronization. This can pose a great challenge particularly in a large cloud computing environment where there are numerous virtual domains, virtual networks, and endpoints.